Implantable prosthetic valve

ABSTRACT

A prosthetic valve for implantation within a fluid conducting lumen within a body includes an elongate generally cylindrical radially collapsible valve body scaffold defining a fluid passageway therethrough for retentive positioning within the lumen. A radially collapsible leaf valve member is supported by the scaffold includes a number of valve leafs deflectable between a closed position restricting fluid flow through the passageway and an open position permitting fluid flow through the passageway. The leaf valve member includes an interior leaf valve frame defining a valve leaf aperture which is sealed by a fluid impermeable non-thrombogenic lining to prevent fluid flow therethrough.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/714,034, filed Nov. 14, 2003, now U.S. Pat No. 6,840,957, which is acontinuation of U.S. application Ser. No. 10/191,667, filed Jul. 9,2002, and now U.S. Pat. No. 6,685,739, which is a division of U.S.application Ser. No. 09/425,142, filed Oct. 21, 1999, now U.S. Pat. No.6,440,164 B1.

FIELD OF THE INVENTION

The present invention relates to the field of implantable prostheses.More specifically, the present invention relates to implantableprosthetic cardiac, aortic, and venous valves.

BACKGROUND OF THE INVENTION

In human pathology, the proper functioning of both cardiac and venousvalves is of paramount importance. Disorders of cardiac valves causesignificant morbidity and mortality. These disorders affect persons ofall ages and can result from congenital or degenerative conditions, aswell as from the sequelae of infections. Stenosis and insufficiency ofthe aortic or mitral valves have a greater incidence than stenosis andinsufficiency of the tricuspid and pulmonary valves. Venousinsufficiency is believed to contribute to various maladies, includingedema, varicose veins, aching leg pain while standing,lipodermatosclerosis, and ulcerations. Venous insufficiency isessentially caused by venous hypertension and chronic venous stasis dueto valvular incompetence both of an idiopathic nature and of a secondarynature following past illnesses of the venous systems.

A prosthetic cardiac or venous valve may regulate the direction of thepulsating blood flow so as to limit the occurrence of blood stasis inthe region about the valve. By maintaining the direction of blood flowtherethrough, a prosthetic cardia, aortic, or venous valve may alleviatethe maladies resulting from valve disorders or venous insufficiency. Aprosthetic valve should therefore permit blood flow in the properpredetermined direction to limit or prevent backflow of the blood in areverse direction.

The art has seen several attempts for providing a prosthetic valve toalleviate the consequences of cardiac valve disorders and of venousinsufficiency. These attempts generally fall into two categories,biologic valves and mechanical valves. Biologic valves are comprised ofa stent supporting a number of circumferential leaflets made of aflexible material. If the material is biologic in nature, it may beeither a xenograft, that is, harvested from a non-human cadaver, or anallograft, that is, harvested from a human cadaver. For example, it isknown in the art to apply a pericardium biological tissue layercovering, for providing the valve leaflets, to a stent which providesstructural annular integrity to the prosthesis. Non-biologic materialsuch as polyurethane has also been used. The second category ofprosthetic valves, mechanical valves, usually comprise a rigid annulussupporting up to three rigid leaflets. The annulus and leaflets arefrequently formed in pyrolitic carbon, a particularly hard and wearresistant form of carbon. The annulus is captured within a sewing ringso that the valve may be attached to tissue at the location of thereplaced valve. Unfortunately, surgically positioning these implantstypically requires suturing or sewing the device into the blood vessel,increasing the risk of thrombosis due to the resulting suturing oranastomoses of the body vessel.

These attempts typically provide a valve structure having a relativelyrigid tubular body structure which supports a flexible valve leafstructure. That is, any structural rigidity imparted to the tubular bodystructure is separated from the valve leaf structure. For example, U.S.Pat. No. 4,759,759 discloses a prosthetic valve having a solid stentmember having a diametrically-opposed upstanding posts and asubstantially cylindrical flexible cover. The two portions of the coverextending between the upstanding stent posts may be collapsed againsteach other in sealing registry over a fluid passageway defined by thestent. The stent, being a solid member, limits the radial collapsingthereof for endoscopic delivery within a body lumen. The cover, beingunsupported by the stent within the fluid passageway of the valve, mustitself provide sufficient strength and resiliency to optimally regulatefluid flow. Alternatively, U.S. Pat. No. 5,855,691 discloses aprosthetic valve having a radially expandable covered stent whichdefines an elongate fluid passageway therethrough. A flexible valve isdisposed within the fluid passageway to regulate fluid flowtherethrough. The valve is formed of a flexible and compressiblematerial formed into a disc with at least three radial incisions to formdeflectable leaflets. While the stent circumferentially supports thevalve body, the leaflets are not supported by any other structure withinthe fluid passageway. There is therefore a need in the art for a unitaryprosthetic valve construction which provides structural reinforcement toboth the tubular body portion of the valve and to the valve leafssupported thereon.

SUMMARY OF THE INVENTION

The present invention is directed to providing a fully prosthetic valvehaving valve leafs formed from a covered valve leaf frame and which maybe implanted using a minimally-invasive, endoscopic technique.

The present invention provides a prosthetic valve for implantationwithin a body lumen. The prosthetic valve of the present inventionprovides a device for regulating and maintaining the direction of apulsating fluid flow through the body lumen. The valve includes aradially-collapsible scaffold portion and a radially-collapsible leafvalve portion. The scaffold portion includes a tubular open bodyscaffold defining a fluid passageway therethrough. The leaf valveportion is deflectable between a closed configuration in which fluidflow through the valve passageway is restricted and an openconfiguration in which fluid flow through the valve passageway ispermitted.

Each of the valve leafs desirably includes a valve leaf frame having anopen construction so as to facilitate radially-collapsing or -expandingthe leaf valve portion of the valve. Each valve leaf frame defines avalve leaf aperture with the scaffold. The present invention seals eachvalve leaf aperture to prevent fluid flow therethrough. The materialused to seal each valve leaf aperture is sufficiently thin and pliableso as to permit radially-collapsing the leaf valve portion for deliveryby catheter to a location within a body lumen. A fluid-impermeablebiocompatible non-thrombogenic valve leaf cover may be positioned oneach valve leaf frame so as to seal the valve leaf aperture. The valveleaf cover may be formed from a surgically-useful textile such asDacron, polyethlylene (PE), polyethylene terephthalate (PET), silk,Rayon, or the like. The valve leaf cover may also be formed of asurgically-useful polymeric material such as urethane,polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene(ePTFE). The valve leaf cover may also coated with a cellulargrowth-inhibiting drug such as Heparin or Taxol or another suchcomposition.

Similarly, each of the valve leaf apertures may be covered with culturedtissue cells derived from a either a donor or the host patient which areattached to the valve leaf frames. The cultured tissue cells may beinitially positioned to extend either partially or fully into each valveleaf aperture. In order to provide additional support to the attachedcultured tissue cells, a microfilter-type support mesh spanning thevalve leaf aperture may also be provided. The present invention furthercontemplates that the supporting scaffold and valve leaf frames may beformed of either a bioabsorbable material or a non-bioabsorbablematerial. It is contemplated that the scaffold and valve leaf frameswhich are formed from a bioabsorbable material will eventually bedisplaced by the tissue cells as the tissue cells mature. Eventually thecells alone will provide the fully functioning valve. Alternatively,when the scaffold and valve leaf frames are formed from anon-bioabsorbable material, the cultured cells provide a means forreducing any undesirable biological response by the host.

The leaf valve member is normally spring biased towards the closedconfiguration. The present invention also contemplates biasing the leafvalve member towards the open configuration to simulate known anatomicalmechanics of a valve in which the leaf valve portion would close uponexperiencing sufficient back flow pressure from the direction downstreamfrom the valve.

The leaf valve portion desirably includes a number of valve leafs whichare deflected between the closed and open configurations when the fluidpressure differential thereacross exceeds a predetermined threshold.That is, the fluid pressure differential acts to open the valve when thefluid pressure upstream of the valve leaf portion is greater than thefluid pressure downstream of the valve leaf portion.

Each of the valve leafs is deflectably supported by the scaffold at aflexible hinge. The present invention contemplates that the open andclosed configurations of the valve may be defined either downstream orupstream of the flexible hinges. It is desired that the scaffold portionof the valve will eventually provide fluid-tight engagement with thebody lumen although it is contemplated that some leaking or fluid flowbetween the scaffold portion and the body lumen is still acceptable.Just as it is preferred, but not required, that the valve leafs preventfluid flow in the closed configuration, it is recognized thatsubstantial restriction of fluid flow past the scaffold-lumen interfacemay still provide a prosthetic valve exhibiting acceptable performancecharacteristics.

The present invention shows and describes both a bicuspid valve and asix-leaf valve, although designs employing a different number of valveleafs are clearly within the scope of the present invention. Thebicuspid valve includes a pair of leaf frames which deflect about ahinge positioned downstream of the closable valve opening. The six-leafvariant includes valve leafs which deflect about hinges positionedupstream of the closable valve opening.

The abutting engagement between adjacent valve leafs, while desirablyproviding a fluid-tight seal, is contemplated to significantly restrictbackflow past the valve leafs. The abutting engagement between adjacentvalve leafs may therefore provide less than complete fluid integritywhile still achieving the desired performance parameters.

The scaffold of the valve includes a first end defining a first opening,a second end defining a second opening, a substantially cylindricalinterior face, a substantially cylindrical exterior face, and at leastone radially-extending scaffold opening communicating between interiorand exterior faces. The interior face generally defines the fluidpassageway. The scaffold and leaf valve member are formed to beexpandable from a first diameter permitting delivery through the bodylumen to a second radially-expanded diameter for retentively engagingthe body lumen at a desired location. The scaffold may be formed havinga shape memory favoring radial self-expansion or may be formed so as topermit radial expansion by a delivery balloon which is deflated andwithdrawn after scaffold expansion against the body lumen. The scaffoldmay further provide at least one radially outwardly projecting hookmember for retentively engaging the fluid conduit when expandedthereagainst.

The present invention also contemplates forming both the scaffold andthe valve leaf frames as a unitary support trellis. The unitary trellismay be formed by a single undulating wire bent to form both the radiallyexpandable scaffold portion and the radially expandable valve leafframes. While various configurations for the unitary support trellis ofthe present invention are contemplated, one preferred configurationbends a wire along a longitudinally extending and retracting undulatingpath so as to alternately define a collapsible and expandable leaf frameaperture and then a collapsible and expandable scaffold aperture. Thewire may be laid along a flat surface so as to form a planar trellispreform. The trellis preform may then be wrapped about an elongatecylindrical mandrel. The valve leaf frames may be deflected about theirrespective hinges to establish a shape memory in either the open orclosed configuration either prior to or after wrapping the trellispreform about the mandrel.

The trellis is desirably formed from a biocompatible metal or polymericmaterial. The trellis may additionally be formed from a shape-memorymaterial to more reliably provide the required geometry to functioneffectively within the valve once radially expanded at a site within alumen. The trellis may be formed from an alloy of nickel and titanium inspecific proportions known in the art as nitinol. Alternatively, thetrellis may be formed from a polymeric material which allows the trellisto be radially collapsed for delivery to a site in a lumen but thenradially expands to return to an undeflected shape so as to functioneffectively within the valve.

The present invention also contemplates attaching an elongate generallycylindrical first biocompatible non-thrombogenic liner to the trellis.The first liner may be positioned on either the interior or exteriorface of the scaffold. The first liner may also provide the sealing coverfor the valve leaf frame apertures. The first liner may be trimmed tospan between adjacent valve leafs in the open configuration so as toprovide a larger surface area for the body fluid to act upon when urgingthe valve leafs between the open and closed configuration. The firstliner may also be trimmed to provide at least one flap extending in thedownstream direction beyond each valve leaf. Each flap may then befolded over the adjacent valve leaf frame and laminated through a valveleaf aperture to the liner.

Furthermore, an elongate generally cylindrical second biocompatiblenon-thrombogenic liner may be positioned on the scaffold opposite thefirst liner. The second liner may desirably extend only along a portionof the scaffold or fully along scaffold. The first and second liners maybe joined so as to fully encase either just the scaffold or the entiretrellis. It is contemplated that the first and second liners may belaminated together through one or more openings defined by the trellis.Additionally, the second liner may be formed by folding the first linerover the first end of the scaffold so as to extend at least partiallyalong the opposite face of the scaffold as the first lining.

Each liner positioned on the trellis may inhibit thrombus formation andfacilitate tissue ingrowth therethrough for assimilating the valve ofthe present invention into the body lumen. Towards this latter goal, oneor both of the liners may be formed from a porous textile or polymericmaterial. It is further contemplated that either liner may be formedfrom an xenograft of cellular tissue from a donor such as bovine cardialtissue, or homograft of cellular tissue formed from the host patient.

It is also contemplated by the present invention that the prostheticvalve may also be attached to the interior surface of a second radiallycollapsible prosthetic fluid conduit. The second fluid conduit may beselected from many known stent and covered stent designs known in theart. The second fluid conduit further maintains the patency of the lumento either side of the valve and may also include a biocompatible fluidimpermeable non-thrombogenic lining on either or both of its own inneror outer surfaces. The materials used to form the second fluid conduitmay also be selected to be either bioabsorbable or non-bioabsorbable asmay be desired.

The present invention is also directed to methods of making theprosthetic valve of the present invention.

While the present invention has been described generally, the presentinvention will be more readily appreciated in a reading of the “DetailedDescription of the Invention” with reference to the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows side elevational view of a prosthetic venous valve of thepresent invention in a closed, flow restricting configuration.

FIG. 2 shows a top elevational view of the prosthetic venous valve ofFIG. 1 in the closed configuration.

FIG. 3 shows a side elevational view of the prosthetic venous valve ofFIG. 1 in an open, flow conducting configuration.

FIG. 4 shows a top elevational view of the prosthetic venous valve ofFIG. 1 in the open configuration.

FIG. 5 shows the unitary support trellis of the prosthetic venous valveof FIG. 1.

FIG. 6 shows a front elevational view of the unitary support trellis ofthe present invention in a flat trellis preform configuration.

FIG. 7 is a side elevational view of the unitary support scaffolding andvalve leaflet frames upon being stressed to provide for a self-closingvalve.

FIG. 8 depicts one step in a method of constructing the prosthetic valveof the present invention by wrapping the unitary support scaffolding andvalve leaflet frames about a non-thrombogenic lining positioned about amandrel.

FIG. 9 shows an isometric view of a unitary support trellis for aprosthetic valve of the present invention.

FIG. 10 shows a perspective view of a prosthetic valve of the presentinvention in an open configuration and in which the scaffold portion ofthe valve is substantially uncovered.

FIG. 11 shows a side elevational view of the prosthetic valve of FIG.10.

FIG. 12 shows a side elevational view of the prosthetic valve of FIG. 10in an open configuration.

FIGS. 13A-D depict a further embodiment of the present invention inwhich adjacent leaf frames are joined at a location therealong to reducethe size of the valve flow opening.

FIG. 14 shows an embodiment a prosthetic valve of the present inventionin which a unitary support trellis is positioned over a liner.

FIG. 15 shows an alternate embodiment of a prosthetic valve of FIG. 14in which a second liner is positioned on the trellis to extend acrossthe proximal end of the scaffold portion.

FIG. 16 is a side elevational view of an alternate embodiment of aprosthetic valve of the present invention in an open, flow-conductingconfiguration in which a non-thrombogenic webbing spans between eachadjacent leaflet of the valve.

FIG. 17 shows an alternate embodiment of the present invention in whicha secondary support scaffolding is formed to the downstream side of thevalve leaflets.

FIG. 18 shows a still further embodiment of the present invention inwhich a number of deflectable valve leafs are attached within thefluid-conducting passageway to a radially-expandable prosthetic supportstructure.

FIG. 19 is a partial cut-away of the embodiment of FIG. 10 depicting thevalve leaflets in a closed, flow-restricting configuration.

FIG. 20 is a partial cut-away of the embodiment of FIG. 11 depicting thevalve leafs in an open, flow-conducting configuration.

FIG. 21 depicts an alternate embodiment of a covered valve leaf of thepresent invention to be attached to a radially expandable outer conduit.

FIGS. 22 and 23 depict a prosthetic bicuspid valve of the prior art inthe open and closed configurations, respectively.

FIGS. 24A-B are respective side and top elevational views of aprosthetic bicuspid valve of the present invention in the closedconfiguration.

FIGS. 25A-B are respective side and top elevational views of aprosthetic bicuspid valve of the present invention in the openconfiguration.

FIGS. 26A-B depict a unitary scaffold for the prosthetic bicuspid valveof FIG. 24 in the closed configuration.

FIG. 26C depicts the scaffold for the prosthetic bicuspid valve of FIG.24 in the open configuration.

FIGS. 27A-B are respective side and top elevational views of anotherembodiment of the prosthetic bicuspid valve of FIG. 24, having a largervalve leaf and shallower valve cusp, in the closed configuration.

FIGS. 28A-B are respective side and top elevational views of theprosthetic bicuspid valve of FIG. 27A in the open configuration.

FIGS. 29A-B are side elevational views of the scaffold of the prostheticbicuspid valve of FIG. 27A and FIG. 28A, respectively.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to method and apparatus forproviding a fluid flow check valve for a body lumen. A preferredembodiment of the present invention is particularly suitable for formingan endoluminal prosthetic valve for vascular applications. Theprosthetic valve of the present invention regulates and maintains thedirection of a pulsating fluid flow through a body lumen. The prostheticvalve of the present invention is configured to open and close inresponse to the fluid pressure differential across the valve. The valveincludes a radially-collapsible scaffold portion and aradially-collapsible leaf valve portion which allows the valve to bedelivered via catheter through the body lumen in which it will beemplaced. The scaffold portion includes a tubular open body scaffolddefining a fluid passageway therethrough. The leaf valve portion isdeflectable between a closed configuration in which fluid flow throughthe valve passageway is restricted and an open configuration in whichfluid flow through the valve passageway is permitted.

The preferred embodiment of the prosthetic valve of the presentinvention is designed to be biased towards a closed, flow-restrictingconfiguration. The valve opens when sufficient fluid pressure is appliedto the leaflets from the upstream direction. Desirably the valve willopen when the pressure differential across the leaflets reaches about1-20 mm Hg. When the pressure differential is too low, the valve closesto prevent back flow. The valve desirably withstands up to about 100 mmHg of back flow pressure. When the pressure differential from bloodflowing the desired direction is removed, the valve returns to theclosed configuration.

As will be described in further detail hereinbelow for the six-leafvariant of the present invention, the leaf valve portion is connected tothe scaffold portion so that the valve leafs are deflectable about anannularly extending hinge line. The location of the hinge line along thelength of the leaf valve portion influences the fluid pressure requiredto open and close the valve. In the closed configuration, the valve leafportion substantially restricts fluid flow through the valve byproviding a biocompatible impermeable non-thrombogenic covering.extending from the hinge line in registry with the passageway.

Referring now to the drawings, FIGS. 1-5 depict a prosthetic valve 10 ofthe present invention. Valve 10 provides a radially-collapsible trellis24 having an open construction. Trellis 24 includes an elongate tubularbody scaffold 30 supporting a number of deflectable valve leaf frames 52deflectable about a hinge line 22. Each valve leaf frame 52 defines aleaf frame aperture 62 which is sealed by a valve cover 80 positioned ontrellis 24. The remainder of trellis 24 may also be covered with one ormore liners 82 and 88, or may be left uncovered altogether. The coveredleaf frames 52 form the deflectable valve leafs 40 which 16 may be movedout of abutting engagement with each other so as to permit fluid flowthrough valve 10 in response to the fluid pressure upstream thereof.

Valve 10 is provided for implantation within the fluid passageway of abody lumen, such as for replacement of a cardial, arterial, or venousvalve, to regulate the flow of a bodily fluid therethrough in a singledirection. Valve 10 is constructed from biocompatible materials so as tominimize any adverse body reaction to the implantation of valve 10.Valve 10 includes an elongate tubular body portion 12 and a leaf valveportion 14. Valve 10 includes an upstream end 16, a downstream end 18,and an elongate fluid passageway 20 extending therebetween along a valveaxis 1 _(v). Leaf valve portion 14 is connected to body portion 12 toextend in overlying registry with passageway 20. Leaf valve portion 14includes one or more valve leafs 40 which are deflectable with respectto body portion 12 about a hinge line 22 between a closed configuration,shown in FIGS. 1 and 2, restricting fluid flow through passageway 20,and an open configuration, shown in FIGS. 3 and 4, permitting fluid flowthrough passageway 20. As shown in FIGS. 13A-D, hinge line 22 may bealternatively formed along the length of valve portion 14 by joiningadjacent valve leafs 40 at a midway location 22′. Locating hinge line 22further downstream from body portion 12 increases the required higherfluid pressure differential to deflect the valve leafs to the openconfiguration.

Leaf valve portion 14 may provide any number of valve leafs 40. Whilesix valve leafs are provided and discussed by reference to FIGS. 1-4, abicuspid valve configuration is also contemplated and will be furtherdiscussed hereinbelow. Still referring to FIGS. 1-4, each of the valveleafs 40 are similarly-sized and -shaped and include opposed first andsecond major surfaces 42 and 44, respectively. Each first major surface42 of a valve leaf 40 is oriented in facing opposition towards upstreamend 16 of valve 10. Each of the valve leafs 40 provide a sawtoothperimetrical edge formed by a first and second leaf edge 46 and 48,respectively, which are positionable in abutting engagement with a leafedge of an adjacent valve leaf 40 to define the closed configuration ofvalve 10. Similarly, as best shown in FIG. 4, the leaf edges 46 and 48define a valve leaf opening 50 when in the open configuration. Valveleaf opening 50 is in fluid communication with passageway 20.

All of the valve leafs 40 are formed having a spring bias towards eitherthe open or the closed configuration. When all of the valve leafs 40 arespring biased towards the closed configuration, the open configurationmay be attained when the fluid pressure acting on the first majorsurfaces 42 of the valve leafs 40 overcomes both the fluid pressureacting on the second major surfaces 44 of the valve leafs 40 of valve 10and any spring bias closing force imparted to the valve leafs 40 actingto close the valve leafs. Should the fluid pressure from the downstreamend 28 of valve 10 become too great relative to the upstream fluidpressure, the valve leafs 40 will also be urged towards the closedconfiguration. Each valve leaf 40 desirably curves inward such that thesecond major surface 44 has a concave shape to better collect backflowand urge the valve leafs 40 towards the closed configuration. Theprosthetic valve 10 of the present invention thereby provides a devicefor regulating and maintaining the direction of a pulsating fluid flowthrough the body lumen. While leaf valve portion 14 is normally springbiased towards the closed configuration, it is also contemplated,however, to bias leaf valve portion 14 towards the open configuration inorder to simulate known anatomical mechanics of certain valves. Thus,when biased towards the open configuration, leaf valve portion 14 wouldclose upon experiencing sufficient back flow pressure from thedownstream end 28 of valve 10.

FIG. 5 shows the unitary support trellis 24 employed by valve 10.Trellis 24 may be formed from a material exhibiting shape memorycharacteristics or from a material which is readily expandable by aballoon catheter. Trellis 24 is generally an elongate tube being coaxialwith valve axis 1 _(v). Trellis 24 has opposed upstream and downstreamends 26 and 28. Upstream end 26 of trellis 24 is further defined by aradially collapsible body scaffold 30. Downstream end 28 of trellis 24is further defined by a radially-collapsible leaf valve framework 32.

Trellis 24 may be formed from a wide variety of materials and in a widevariety of configurations. Radially-expandable endovascular stents knownin the art provide useful basic designs for modification into a supporttrellis of the present invention and may be formed in a wide variety ofconfigurations. One example of a stent useful in the present inventionis a slotted tubular stent which is designed to radially expand eitherby balloon catheter or by forming the stent from a temperature-sensitivememory alloy which changes shape at a designated temperature ortemperature range. Other stent types, such as tubular-shaped wire stentsand self-expandable spring-biased stents are also contemplated. Trellis24 may therefore be formed from a variety of materials includingstainless steel, titanium, platinum, gold and other bio-compatiblemetals. Shape memory plastics, polymers, and thermoplastic materialswhich are inert in the body may also be employed to form trellis 24.Shaped memory alloys having superelastic properties generally made fromspecific ratios of nickel and titanium, commonly known as nitinol, areamong the preferred trellis materials,

With additional reference to FIG. 9, scaffold 30 is a substantiallycylindrical member having an interior face 34, an exterior face 36 anddefines at least one radially-extending scaffold opening 38communicating therebetween. Interior face 34 of scaffold 30 generallydefines passageway 20. It is contemplated by the present invention thatscaffold opening 38 need not be completely perimetrically bounded byscaffold 30. Scaffold 30 is formed to have a generally openconfiguration including a plurality of openings 38 communicating betweeninterior face 34 and exterior face 36. These openings 38 provide forlongitudinal flexibility of valve 10 as well as to permit valve 10 to beradially collapsed for delivery through, and radially expanded fordeployment in, a body lumen such as a blood vessel. Furthermore,scaffold 30 preferably maintains a substantially coaxial alignment withthe body lumen as leaf valve portion 14 deflects between the open andclosed configurations so as to better seal passageway 20 when valve 10is closed.

Leaf valve framework 32 includes a leaf frame 52 corresponding to eachvalve leaf 40 of leaf valve portion 14. Each leaf frame 52 includes afirst and second elongate component legs 54 and 56, respectively. Eachleaf frame 52 also has a length which is greater than the radius of theradially-expanded scaffold when implanted so as to minimize the risk ofa valve leaf 40 over-deflecting about hinge line 22 towards upstream end16 of valve 10. Each component leg 54 and 56 includes a proximal end 54a and 56 a, and an opposed distal end 54 b and 56 b, respectively. Eachleaf frame 52 is joined to scaffold 30 at a flexible hinge 60 defined bythe junction of the proximal ends 54 a and 56 a of each leg componentwith scaffold 30. For each valve leaf 40, hinge 60 includes space-aparthinge components 60 a, and 60 b. Additionally, the distal ends 54 b and56 b are contiguously formed. Each hinge component 60 a, 60 b may berespectively joined to the adjacent hinge component 60 b, 60 a of theadjacent leaf frame 52 in order to provide improved sealing of valve 10in the closed configuration. The joining of the hinge components 60 aand 60 b of adjacent valve leafs 40 further defines annular hinge line22.

Each leaf frame 52 defines a leaf frame aperture 62 with the distalextent 31 of scaffold 30. Leaf frame aperture 62 communicates betweenthe first and second major surfaces 42 and 44 of valve leaf 40. Theshape of leaf frame 52 is selected so as to assist and not inhibit theradial contraction of valve 10 for delivery via catheter through a bodylumen. Additionally, leaf frame 52 is formed having a curve impartedthereto so as to provide a concave shape to second major surface 44 ofleaf 40. Each leaf frame 52 is imparted with a shape memory so as toextend over passageway 20 in either the open or closed configuration.

Trellis 24 is preferably formed by a single wire 70 contoured to formboth scaffold 30 and leaf valve frame 32. As shown in FIG. 6, wire 70may trace a pattern on a flat surface so as to form a trellis preform74. Wire 70 may be longitudinally extended and retracted in anundulating pattern such that a valve leaf frame aperture 62 is formedand then a scaffold opening 38 is formed, although other paths arepossible. Each leaf frame aperture 62 and each scaffold opening 38 areperimetrically defined by a segment of wire 72 which allows trellis 24to be radially-collapsible to allow delivery of valve 10 through a bodylumen and then radially-expanded at a selected lumen site. Moreover,wire 70 may be welded, fused, crimped, sutured, or otherwise, joinedtogether at strategic locations such as at a scaffold joint 76 definedbetween circumferentially-adjacent scaffold openings 38. Additionally,wire 70 may be joined at or about hinge joints 76 where adjacent hingeportions 60 a and 60 b of adjacent valve leaf frames abut.

Referring to FIGS. 7 and 8, trellis preform 74 is bent into the shape oftrellis 24 by wrapping preform 74 about an elongate cylindrical mandrel78 and joining trellis perform ends 74 a and 74 b together, and thendeflecting the leaf frames 52 about hinge line 22 into overlyingregistry with passageway 20. Trellis 24 may be heat set in thisconfiguration by a method as is typically known for the material whichforms trellis 24.

The present invention seals each leaf frame aperture 62 to prevent fluidflow therethrough. The material used to seal each leaf frame aperture 62is sufficiently thin and pliable so as to permit radially-collapsing theleaf valve portion for delivery by catheter to a location within a bodylumen. Referring to FIGS. 10-12, a fluid-impermeable biocompatiblenon-thrombogenic valve leaf cover 80 may be positioned on trellis 24 soas to seal the leaf frame apertures 62. Preferably, valve leaf cover 80seals the entire expanse of each leaf frame aperture 62 prior toimplantation although it is recognized that the lumen wall will alsoassist in sealing leaf frame aperture 62 in the region about scaffold 30adjacent hinge line 22. Therefore, valve leaf cover 80 should minimallyseal leaf frame aperture 62 between component legs 54 and 56 and hingeline 22 so that as scaffold 30 becomes embedded in the lumen wall, valve10 will fully seal at hinge line 22. Valve leaf cover 80 may be formedfrom a thin layer of, by way of illustration and not by limitation, PE,Pellethane, Urethane, bovine pericardial tissue, and the like.Alternatively, Valve leaf cover may be formed from a surgically-usefultextile including, by way of illustration and not by limitation, Dacron,Polyethylene terephthalate (PET), Polyethlylene (PE), silk, Rayon, orthe like. Valve leaf cover 80 may also be formed of a surgically-usefulpolymeric material including, by way of illustration and not bylimitation, polytetrafluoroethylene (PTFE) or expandedpolytetrafluoroethylene (ePTFE). Valve leaf cover 80 is desirably coatedwith a cellular growth-inhibiting drug such as Heparin or Taxol or thelike.

Similarly, each valve leaf aperture 62 may be covered with culturedtissue cells derived from a either a donor or the host patient. Thecultured tissue cells may be attached to each leaf frame 52 to thedistal extent 31 of scaffold 30 so as to seal each valve leaf aperture62. The cultured tissue cells may be initially positioned on a microfilter type mesh so as to extend either partially or fully into eachvalve leaf aperture 62. Scaffold 30 and leaf frames 52 may be formed ofeither a bioabsorbable material or a non-bioabsorbable material so thateach will eventually be displaced by the tissue cells as the tissuecells mature. Eventually, then, the cells alone will provide the fullyfunctioning valve, Alternatively, when scaffold 30 and leaf frames 52are formed from a non-bioabsorbable material, the cultured cells providea means for reducing any undesirable biological response by the host.

FIGS. 13A-D depict a still further embodiment of the present inventionin which adjacent valve leaf frames 24 are joined at a location alongthe length thereof so as to provide a smaller opening 50′ in the openconfiguration. Adjacent component legs 54 and 56 may be joined bywelding or other techniques so as to form a hinge line 22′ at a locationdownstream from the distal extent 31 of scaffold 30. As the size ofopening 50 affects the required actuation pressure differential actingupon the valve leafs 40, it is contemplated that the precise location atwhich adjacent valve leaf frames 24 are joined may be selected inaccordance with the fluid flow pressure parameters at the site withinthe body in which the valve of the present invention is emplaced.

Referring again to FIGS. 1-4 and with additional reference to FIGS.14-16, an elongate generally cylindrical first biocompatiblenon-thrombogenic liner 82 is attached to trellis 24. First liner 82 maybe positioned over either of interior face 34 or exterior face 36 ofscaffold 30. First liner 82 may also be provided in addition to, or inplace of, valve leaf cover 80 for sealing the leaf frame apertures 62.FIG. 15 depicts first liner 82 positioned on the interior 34 of scaffold30. Furthermore, first liner 82 may be trimmed to conform closely to thevalve leaf frames, as shown in FIG. 15. As shown by FIG. 16, first liner82 may include a valve webbing 84 trimmed to span between the edges ofadjacent valve leafs in the open configuration so as to provide a largersurface area for the body fluid to act upon when urging the valve leafs40 between the open and closed configuration. First liner 82 may also betrimmed to provide at least one flap 86 extending in the downstreamdirection beyond each valve leaf 40. Each flap 86 may then be foldedthrough the adjacent valve leaf aperture 62 and laminated to the firstliner spanning the other major surface.

Similarly, an elongate generally cylindrical second biocompatiblenon-thrombogenic liner 88 may be positioned on scaffold 30 oppositefirst liner 82. Second liner 88 may extend only along a portion ofscaffold 30, as shown in FIG. 15, or fully along trellis 24, as shown inFIG. 16. The first and second liners may be joined so as to fully encaseeither just scaffold 30 or all of trellis 24. Numerous techniques may beemployed to laminate or bond first liner 82 to second liner 88 throughthe scaffold openings 38 and the leaf frame apertures 62 of trellis 34including heat setting, adhesive welding, application of uniform forceand other bonding techniques. Additionally, second liner 88 may beformed by folding an extended length of first liner 82 over upstream end26 of scaffold 30 so as to extend at least partially along the oppositeface of scaffold 30 as first liner 82.

Each of liners 82 and 88 may be capable of inhibitting thrombusformation. Additionally, liners 82 and 88 may either prevent orfacilitate tissue ingrowth therethrough, as the particular applicationfor the valve may dictate. For example, liner 88 may be formed from aporous material to facilitate tissue ingrowth therethrough while liner80 is formed from a material or a treated material which inhibits tissueingrowth. Liners 80 and 88 may be formed from a surgically-usefultextile including, by way of illustration and not by limitation, Dacron,Polyethylene terephthalate (PET), Polyethlylene (PE), silk, Rayon, orthe like, Valve leaf cover 80 may also be formed of a surgically-usefulpolymeric material including, by way of illustration and not bylimitation, polytetrafluoroethylene (PTFE) or expandedpolytetrafluoroethylene (ePTFE). It is further contemplated that eitherliner 82 and 88 may be formed from an xenograft of cellular tissue froma donor such as bovine cardial tissue, or homograft of cellular tissueformed from the host patient.

The polymeric liners 82 and 88 and valve cover 80 of the presentinvention may be formed by a variety of methods. For example, extrusionprocesses such as ram extrusion; polymeric casting techniques such assolvent casting and film casting; molding techniques such as blowmolding, injection molding and rotational molding; and otherthermoforming techniques useful with polymeric materials may be employedand chosen to best serve the type of material used and specificcharacteristics of the liner or cover desired.

While either or both of the polymeric liners 80 and 88 may be provideddirectly in tubular form, i.e as an extruded tube, either one or bothcan also be formed from extruded sheets of material which can be wrappedaround all or a portion of the support scaffold to form a cover orliner. Combinations of sheets and tubes are also contemplated and may beapplied to the support scaffold in a manner essentially as taught byU.S. patent application Ser. No. 09/035,501, which is hereinincorporated by reference. For example, in one embodiment a sheet may befirst formed and wrapped externally about the support scaffold andseamed along the longitudinal axis to form a cover. Such a sheet may bemade with a high degree of uniaxial orientation. The relative axis oforientation of the stent may vary depending on the material used to formthe liner or cover and the orientation and size of its pore structure.For example, in applicants' aforementioned copending U.S. applicationSer. No. 08/721,834, the extruded material used to form the liner orcover may be formed from unsintered ePTFE sheets which have beenexpanded longitudinally and aligned generally longitudinally along thelongitudinal stent axis, transverse to the longitudinal direction, or inan off-axis angle therebetween. In another example, a sheet or tube ofePTFE may be stretched and sintered several times to create a preformedePTFE having expansion memory, such as shown in PCT Publication No. WO96/00103 (Application No. U.S./95/07326), which is herein incorporatedby reference. This publication is based on U.S. priority applicationSer. No. 08/265,794, filed Jun. 27, 1994, which is also hereinincorporated by reference. The preformed ePTFE allows for furtherexpansion once the stent is implanted and radially deployed. Otherembodiments of the present invention include the use of one or moretubes, providing a tube and a sheet formed into a tubular structure, orproviding a plurality of sheets formed into a tubular structure oneither surface of the stent.

Various bioeffecting agents may also be included in the liners by wellknown methods. For example, anti-infective agents and/orantithrombogenic agents may be coated on the liner or disposed withinsome of the pores of the polymeric cover or conformal layer prior toimplantation. Additionally, such bioeffecting agents may also beemployed on the stent or in the anchoring material used thereon. Oneexample is shown in commonly assigned International Patent ApplicationNo. WO 95/29647, published on Nov. 9, 1995 and its 27 U.S. priorityapplications Ser. No. 235,300, filed Apr. 29, 1994, and Ser. No.350,233, filed Dec. 1, 1994, which are incorporated herein by reference.

Referring again to FIG. 8, a method of forming a composite endoluminaldevice of the present invention includes the steps of providing an innerliner 82 on an elongate cylindrical mandrel 78. Trellis 24 is positionedover liner 82. Trellis 24 may be positioned over liner 82 such that anextent 80 a of liner 82 may be folded over the upstream end 26 oftrellis 24 and positioned over an extent of the exterior face ofscaffold 30, as shown in FIG. 15. Extent 80 a may be affixed to liner 82through the scaffold openings 38 or affixed to scaffold 30 itself.Extend 80 a may be positioned over the entire length of trellis 24, asshown in FIGS. 1 and 3. Alternatively, a second liner 88 may bepositioned on trellis 24 opposite first liner 82.

Still referring to FIG. 8, mandrel 78 may be formed to include a shapedend 78 a to serve as a die for shaping the closed configuration of thevalve. Shaped end 78 a includes a contoured impression 78 c for eachvalve leaf 40. Each valve leaf 40 may be deflected against its contouredimpression 78 c to provide abutting engagement between the adjacentvalve leafs. Trellis 24 may be shaped by shaped end 78 a either prior toor after covering with liners 80 or 88. It may be desirable to impartthe shape memory to trellis 24 prior attaching the liners. Additionally,while the leaf valve framework 32 is conformed to shaped end 78 a, thevalve leafs 40 may be joined in accordance with the embodiment of FIGS.13A-D, either before or after attaching one or both of liners 80 and 88.It is further contemplated that each impression 78 c may itself providea contoured surface for imparting a curve to the deflected valve leafs40.

The present invention further contemplates positioning trellis 24 aboutmandrel 78 without an underlying lining. Trellis 24 may then receivefirst lining over only the exterior face 36 of scaffold 30. Lining 80may further be extended so as to cover the leaf frame apertures 62 ofleaf valve frame 52, although it is contemplated using a differentmaterial to cover the leaf frame apertures 62. Lining 80 may alsoprovide a valve webbing spanning between adjacent valve leafs 40.

It is additionally contemplated by the present invention to leavescaffold 30 substantially uncovered and to seal each leaf frame aperture62 to the extent required to provide an acceptable degree of flowrestriction in the closed configuration. While leaf frame apertures 62are desirably fully sealed prior to implantation, it is contemplatedthat only that portion of leaf frame aperture 62 which extends inregistry with fluid passageway 20 be sealed by one or more liners 80.The embedding of scaffold 30 into the body lumen would thereby providevalve 10 with an acceptable degree of fluid-integrity about the lumenwall. In such an embodiment, valve leaf cover 80 may be applied totrellis 24 to fully seal leaf frame aperture 62. The preferred methodincludes attaching a cover to both frame component legs 54 and 56 and tothe segment of distal scaffold extent 31 between the correspondinghinges.

Liners 82 and 88 may be formed of a polymeric material which may befused by various techniques such as heat sealing, solvent bonding,adhesive bonding, or use of coatings. It is also contemplated thatliners 80 and 88 may be formed of a textile material, or that each couldinclude a homograft or xenograft tissue retained by the intermediatemember to seal the openings in same. The formation, application, andorientation of liners 80 and 88 may be accomplished by the techniquesdescribed in commonly-assigned and copending U.S. patent applicationSer. No. 09/035,501, entitled “Conformal Laminate Stent Device”, whichis incorporated by reference herein.

FIG. 17 shows an alternate embodiment of a trellis 148 for valve 110 inwhich trellis 30 of valve 10 is mechanically joined to a second radiallycollapsible scaffold 150. It is also contemplated that trellis 30 ofvalve 10 may be continuously formed by the same wire 170 which formssecond scaffold 150. The present invention contemplates that elongateportions 170 a of wire 170 may be employed between sections of scaffoldsto allow the prosthetic valve 10 to be emplaced withintortuously-extending sections of body lumen.

FIGS. 18-21 depict yet another embodiment of the present invention inwhich the valve leafs of an implantable prosthetic valve 110 areattached to the interior luminal surface 114 of a second radiallycollapsible tubular fluid conduit 112. Second conduit 112 may beselected from many known stent and covered stent designs known in theart. Second conduit 112 further maintains the patency of the body lumento either side of valve 10 and may also include a biocompatible fluidimpermeable non-thrombogenic lining 116 on either or both of its owninterior or exterior lumenal surfaces, 114 and 115, respectively. Thematerials used to form the second tubular fluid conduit may also beselected to be either bioabsorbable or non-bioabsorbable as previouslydescribed for liners 80 and 88.

Second conduit 112 includes a radially collapsible skeleton 120 whichmay be formed from a shape memory alloy, an elastic metal, or a polymer.Second conduit 112 may also be formed of a bioabsorbable material. Outersurface 115 of second conduit 112 need not be covered as skeleton 120will eventually embed into the lumen wall, but a lining 116 may bepreferable so as to limit flow-around until that time.

As shown in FIG. 19, a non-absorbable tether line 125 may have ends 125a and 125 b affixed between second conduit 112 and each valve leaf 40 toprevent the leafs from inverting towards the upstream end 126 ofsecondary conduit should the back flow pressure become sufficient toover-deflect the leafs past hinge line 22. Tether line 125 is desirablyaffixed at ends 125 a and 125 to non-bioabsorbable components of valve110.

With additional reference to FIG. 21, it is also contemplated by thepresent invention to mechanically attach a number of covered leaf frames130 to the interior luminal surface 114 of second conduit 112. Coveredleaf frames 130 are similar in construction to valve leafs 40 of valve10. Each covered leaf frame 130 includes a first and second elongatecomponent leg 132 and 134 welded or otherwise affixed to skeleton 120 ata hinge portion 135 comprising hinges 135 a and 135 b where thecomponent legs attach. Covered leaf frame 130 defines a leaf frameaperture 136 with skeleton 120 between the associated hinges 135 a and135 b. A leaf cover 140 is desirably affixed over each leaf frameaperture 136 by spanning from each component leg 132 and 134 to skeleton120 between the hinges 135 a and 135 b so as to provide a fluidintegrity to the valve in the closed configuration. Alternatively, thecovered leaf frames could be attached to surface 114 along a leaf framestem 130 a.

Referring now to FIGS. 22 and 23, a prosthetic bicuspid valve 900 of theprior art is depicted. Valve 900 is typical of a bubble valve designwhich provides first and second valve leafs, 902 and 904. Valve 900 isformed having a solid interior stent frame which provides a pair ofopposed raised posts which form raised hubs 906 a and 906 b. Theinterior stent is covered with a generally cylindrical cover 908 whichitself is formed of a flexible material. Valve flaps 902 and 904 areformed by the portion of cover 908 extending unsupported beyond theinterior stent structure. Valve flaps 902 and 904 must therefore rely onthe resiliency and shape memory of the material of the cover 908 for anybias towards the open or closed configurations, As shown in FIG. 23,cover 908 terminates at a flap edge 910 which, in the openconfiguration, defines a substantially circular opening through valve900. In the closed configuration, shown in FIG. 22, flap edge 910extends along a substantially catenary path between raised hubs 906 aand 906 b to seal valve 900.

FIGS. 24A-26 depict a prosthetic bicuspid valve 210 of the presentinvention. With like numbers indicating like components to otherembodiments of the present invention, bicuspid valve 210 is a bubblevalve including a support trellis 224 and a fluid impermeablenon-thrombogenic lining 280. Valve 210 is contemplated as a replacementaortic valve. Valve 210 is constructed from biocompatible materials soas to minimize any adverse body reaction to its implantation.

Valve 210 includes an elongate tubular body portion 212 and a leaf valveportion 214. Valve 210 includes an upstream end 216, a downstream end218, and an elongate fluid passageway 220 extending therebetween along avalve axis 1 _(v). Leaf valve portion 214 extends in overlying registrywith passageway 220 and includes first and second valve leafs 240 and241 which are deflectable between a closed configuration, shown in FIGS.24A and 24B, restricting fluid flow through passageway 220, and an openconfiguration, shown in FIGS. 25A and 25B, permitting fluid flow throughpassageway 220. Valve 210 also includes a pair of diametrically-opposedvalve hinge hubs 242 and 244 about which valve leafs 240 and 241 deflectbetween the open and closed configurations. Hinge hubs 242 and 244 arelocated downstream of valve leafs 240 and 241 when valve 210 is in theclosed configuration.

Valve leafs 240 and 241 are similarly-sized and -shaped and includeopposed first and second major surfaces 240 a, 241 a and 240 b, 241 b,respectively. Each first major surface 240 a, 241 a of a valve leaf 240is oriented in facing opposition towards upstream end 216 of valve 210.Valve leafs 240 and 241 further include an arcuate leaf edge 240 c and241 c, respectively, which are positionable in abutting engagement alonga substantially catenary curve between hinge hubs 242 and 244 to definethe closed configuration of valve 210. Similarly, as best shown in FIG.4, the leaf edges 240 c and 241 c define an eye-shaped valve leafopening 250 when in the open configuration. Valve leaf opening 250 is influid communication with passageway 220. Whereas the valve leafs of thesawtooth valves of the present invention desirably had a longitudinallength greater than the radius of the implanted scaffold, valve leafs ofthe bicuspid valves of the present invention may be formed having alongitudinal length dimension 1 which is smaller than the radius of theimplanted scaffold portion.

Valve leafs 240 and 241 are desirably formed having a spring bias abouthinge hubs 242 and 244 towards the closed configuration. The openconfiguration may be attained when the fluid pressure acting on thefirst major surfaces 240 a and 241 a of the valve leafs 240 and 241overcomes both the fluid pressure acting on the second major surfaces240 b and 241 b of the valve leafs 240 of valve 210 and the spring biasimparted to the valve leafs 240 acting to close the valve leafs.Similarly, when the fluid pressure from the downstream end 218 of valve210 become too great relative to the upstream fluid pressure, the valveleafs 240 will be urged towards the closed configuration to thwart fluidflow through the valve back towards the upstream end 228.

FIGS. 26A-C show the support trellis 224 employed by valve 210. Trellis224 may be formed from a material exhibiting shape memorycharacteristics or from a material which is readily expandable by aballoon catheter. Trellis 224 is generally an elongate tube beingcoaxial with valve axis 1 _(v). Trellis 224 has opposed upstream anddownstream ends 226 and 228. Upstream end 226 of trellis 224 is furtherdefined by a radially collapsible body scaffold 230. Downstream end 228of trellis 224 is further defined by a radially-collapsible leaf valveframework 232.

Trellis 224 may be formed from a wide variety of materials and in avariety of configurations. Radially-expandable endovascular stents knownin the art provide useful basic designs for modification into a supporttrellis of the present invention and may be formed in a wide variety ofconfigurations. One example of a stent useful in the present inventionis a slotted tubular stent which is designed to radially expand eitherby balloon catheter or by forming the stent from a temperature-sensitivememory alloy which changes shape at a designated temperature ortemperature range. Other stent types, such as tubular-shaped wire stentsand self-expandable spring-biased stents are also contemplated. Trellis224 may therefore be formed from a variety of materials includingstainless steel, titanium, platinum, gold and other bio-compatiblemetals. Shape memory plastics and thermoplastic materials which areinert in the body may also be employed to form trellis 224. Shapedmemory alloys having superelastic properties generally made fromspecific ratios of nickel and titanium, commonly known as nitinol, areamong the preferred trellis materials.

Scaffold 230 is a substantially cylindrical member having an interiorface 234, an exterior face 236 and defines at least oneradially-extending scaffold opening 238 communicating therebetween.Interior face 234 of scaffold 230 generally defines passageway 220. Itis contemplated by the present invention that scaffold opening 238 neednot be perimetrically bounded by scaffold 230. Scaffold 230 is formed tohave a generally open configuration including a plurality of openings238 communicating between interior face 234 and exterior face 236. Theseopenings 238 provide for longitudinal flexibility of valve 210 as wellas to permit valve 210 to be radially collapsed for delivery through,and radially expanded for deployment in, a body lumen such as a bloodvessel. Furthermore, scaffold 230 preferably maintains a substantiallycoaxial alignment with the body lumen as leaf valve portion 214 deflectsbetween the open and closed configurations so as to better sealpassageway 220 when valve 210 is closed.

Leaf valve framework 232 includes leaf frames 252 and 253 correspondingto valve leafs 240 and 241. Leaf frames 252 and 253 define leaf frameapertures 262 and 263 with the distal extent 231 of scaffold 230. Leafframe apertures 262 and 263 communicate between first and second majorsurfaces 240 a and 240 b of valve leaf 240, and first and second majorsurfaces 241 a and 241 b of valve leaf 241, respectively. Leaf frames252 and 253 may be radially contracted towards valve axis 1 _(v), fordelivery via catheter through a body lumen. Leaf frames 252 and 253 areimparted with a shape memory so as to extend over passageway 220 onceimplanted in a body lumen.

Leaf valve framework 232 further includes diametrically opposed hingeposts 245 and 247 extending from distal end 231 of scaffold 230 towardshinge hubs 242 and 244, respectively. Hinge hubs 242 and 244 extendtransversely to valve axis 1 _(v). Arcuate frame portions 257 and 259 ofvalve leafs 240 and 241 extend between hinge hubs 242 and 244 along asubstantially catenary path. As shown in FIGS. 25B and 26C, arcuateframe portions 257 and 259 deflect about hinge hubs 242 and 244 andswings towards and away from each other as valve leafs 240 and 241 areurged between the closed and open configurations.

Each leaf frame aperture 262 and each scaffold opening 238 areperimetrically defined by a segment of wire 270 which allows trellis 224to be radially-collapsible so as to allow delivery of valve 210 througha body lumen and then radially-expanded at a selected lumen site.Moreover, wire 270 may be welded, fused, crimped, sutured, or otherwise,joined together at strategic locations, such as at a scaffold joint 276defined between circumferentially-adjacent scaffold openings 238.

Trellis 224 is preferably formed by a single wire 270 contoured to formboth scaffold 230 and leaf valve frame 232. Wire 270 may belongitudinally extended and retracted in an undulating pattern such thatone half of scaffold 230 is formed and a then a portion or all of valveleaf frame 232 prior to completing scaffold 230, although other pathsare possible. Alternatively still, trellis 224 may be formed inconstituent components which are then joined. Other methods for formingtrellis 224 as a unitary member will thus be apparent to those skilledin the art.

Liner 280 may be formed in accordance with the description for liner 80hereinabove. Liner 280 may be applied to trellis 224 at either interiorface 234, exterior face 236, or at both faces. Liner 280 may further beaffixed only to trellis 224 or may include portions which are adhered toitself through the scaffold openings 238 and/or the leaf frame apertures262 and 263. It is contemplated that one of inner liner 280 a and outerliner 280 b may be forced though trellis 224 to be affixed to the otheror both may be joined together within the scaffold openings 238 or theleaf frame apertures 262, 263.

The present invention further contemplates that the liner 280 formingthe major surfaces of valve leafs 240 and 241 are urgable into a concaveshape so as to better collect backflow and urge the valve leafs towardsthe open or closed configuration. The major surfaces of valve leafs 240and 241 have complex shapes which are a function of the longitudinalspacing of catenary frame portion from distal end 23 1 of scaffold 230.Furthermore, the material forming the major surfaces need nottaughtly-extend across the leaf frame openings of valve leafs 240 and241. The present invention contemplates providing sufficient excessmaterial spanning leaf frame apertures 262 and 263 such thatoverwhelming fluid pressure acting on one major surface of a valve leafforces the covering through the valve leaf opening. When excess materialis applied across valve leaf apertures 262 and 263, then the first majorsurfaces of each valve leaf 240 and 241 may assume a concave shape so asto favor the opening the valve leafs and the second major surfaces mayassume a concave shape so as to favor closing the valve leafs.

FIGS. 27A-29B depict an alternate embodiment of a bicuspid valve of thepresent invention. Valve 310 is similar in most respects to valve 210described hereinabove but includes valve leafs 340 and 341 defined byleaf frame edges 357 and 359 having larger radius of curvature betweenhinge hubs 342 and 344 than is shown in FIGS. 2-5. The larger radius ofcurvature along leaf frame edges 357 and 359 results in larger majorsurfaces for the opposed valve leafs 340 and 341 and defines a smalleropening 350 in the open configuration, as shown in FIG. 28B. It iscontemplated that leaf frame edges 357 and 359 are deflectable to aposition coextensive with hinge hubs 342 and 344, as shown in FIG. 29B,or to a position downstream of hinge hubs 342 and 344, as shown in FIG.28B. It is also contemplated that the first major surfaces 340 a and 341a may come into contact when valve leafs 340 and 341 are in the closedconfiguration.

While the present invention has been shown and described in detailabove, it will be clear to the person skilled in the art that changesand modifications may be made without departing from the spirit andscope of the invention. That which is set forth in the foregoingdescription and accompanying drawings is offered by way of illustrationonly and not as a limitation. The actual scope of the invention isintended to be defined by the following claims.

1. A valve, comprising: a radially-elastic scaffold with valve leafletframes having an open-frame construction; and an elongate liner adjacentthe radially-elastic scaffold and valve leaflet frames to provide afluid passageway, where the elongate liner includes excess material toprovide a concave shape to the elongate liner extending into theopen-frame construction, and where the valve leaflet frames with theelongate liner move between a closed position to restrict fluid flowthrough the fluid passageway and an open position to allow fluid flowthrough the passageway.
 2. The valve of claim 1, further including amicrofilter support mesh over the open-frame construction of the valveleaflet frames to support cultured tissue cells seeded on to theelongate liner.
 3. The valve of claim 1, wherein the valve leafletframes of the radially-elastic scaffold are mechanically biased towardsthe open position.
 4. The valve of claim 1, wherein the valve leafletframes of the radially-elastic scaffold are mechanically biased towardsthe closed position.
 5. The valve of claim 1, wherein the elongate lineris positioned over the radially-elastic scaffold and a second liner ispositioned on the radially-elastic scaffold opposite the elongate liner.6. The valve of claim 1, wherein the radially-elastic scaffold attachesto an interior surface of a second radially collapsible prosthetic fluidconduit.
 7. The valve of claim 6, wherein the second radiallycollapsible prosthetic fluid conduit is a stent.
 8. A valve, comprising:a radially deformable unitary open-frame scaffold having a tubular bodyand valve leaflet frames; and a liner at least partially encasing theradially deformable unitary open-frame scaffold to provide a fluidpassageway, where the liner includes excess material to provide aconcave shape to the liner extending into the open-frame scaffold, andwhere the valve leaflet frames with the liner move between a closedposition to restrict fluid flow through the fluid passageway and an openposition to allow fluid flow through the passageway.
 9. The valve ofclaim 8, further including a flexible hinge supporting each of the valveleaflet frames on the tubular body.
 10. The valve of claim 8, whereinthe radially deformable unitary open-frame scaffold expands from a firstdiameter to a second radially-expanded diameter.
 11. The valve of claim10, wherein the radially deformable unitary open-frame scaffold expandsthrough the use of a delivery balloon.
 12. The valve of claim 10,wherein the radially deformable unitary open-frame scaffold is formedfrom a shape memory material that self-expands from the first diameterto the second radially-expanded diameter.
 13. The valve of claim 8,wherein the elongate liner is positioned over the radially deformableunitary open-frame scaffold and a second liner is positioned on theradially deformable unitary open-flame scaffold opposite the elongateliner.
 14. A medical system, comprising: a valve having: aradially-elastic scaffold with valve leaflet frames having an open-frameconstruction; and an elongate liner adjacent the radially-elasticscaffold and valve leaflet frames to provide a fluid passageway, wherethe elongate liner includes excess material to provide a concave shapeto the elongate liner extending into the open-frame construction, andwhere the valve leaflet frames with the elongate liner move between aclosed position to restrict fluid flow through the fluid passageway andan open position to allow fluid flow through the passageway; and asecond radially collapsible prosthetic fluid conduit, wherein theradially-elastic scaffold attaches to an interior surface of the secondradially collapsible prosthetic fluid conduit.
 15. The medical system ofclaim 14, wherein the second radially collapsible prosthetic fluidconduit is a stent.
 16. The medical system of claim 14, wherein thevalve leaflet frames of the radially-elastic scaffold are mechanicallybiased towards the open position.
 17. The medical system of claim 14,wherein the valve leaflet frames of the radially-elastic scaffold aremechanically biased towards the closed position.
 18. The medical systemof claim 14, wherein the elongate liner is positioned over theradially-elastic scaffold and a second liner is positioned on theradially-elastic scaffold opposite the elongate liner.